The Quantum Universe (available also as video)

Apparently everything that can happen does happen... eventually. Brian Cox discusses this and other probabilities, such as quantum mechanics, the Higgs mechanism and condensate, which can all be found in his book on these matters, The Quantum Universe.

Transcript

Robyn Williams: So how about this; anything that can happen, does happen. Will this mean you will remain forever 32 and become as rich as Gina and Clive? Let's ask Brian Cox, he should know.

The Science Show is full of penguins and omega-3 oils for your muscles, and we'll also ask whether the arts may be vital for our culture as well as the sciences, and discover Jeremy Tear, the man from 34 years ago Matt Peacock was looking for last week.

Hello, I'm Robyn Williams.

But could I be Justin Bieber instead? Why not, if everything that can happen does happen. That's the title of a book on the quantum universe by Brian Cox who brought us the superb TV series Wonders of the Universe and Wonders of the Solar System.

Is it true that everything that can happen does happen?

Brian Cox: Yes, in a technical sense. What you do, you ask the question, which is all that quantum mechanics tells you really, is I have a particle here at one point and I want to know the probability of it being over here at the next point. What do you do? Well, technically what you do is you add up a quantity, it's called the action actually, but it doesn't matter what it is, you basically consider the particle moving in every possible path from A to B. And Feynman's approach is to do that mathematically. So add up a set of quantities for each possible way something can go from one place to the other, and you get the probability out in the end and it will actually be in the vicinity of that point at some future time. So it's a statement of technical fact, in a way, about how you do calculations in quantum theory.

Robyn Williams: Of course the public will immediately infer that everything that can happen in the world does happen.

Brian Cox: Well, I think I'm a member of the 'shut up and calculate' school of physics. Quantum mechanics works, it's the way we design transistors et cetera, it is our best explanation of everything in the universe other than gravity. The problem with the theory in an interpretive sense is that you ask the question, well, we accept the fact that atoms behave in a strange way, and also the theory does tell you how classical behaviour, so the behaviour of cups and people and things, how that emerges from the theory, but you still have this problem that when you try to interpret it as a theory of big things, then you get these Schrödinger's cat type problems where things are indeed...everything that can happen is happening; cats can be alive and dead, people can be in an infinite number of places at once. And so it's how you interpret that.

The problem really is it's a probabilistic theory, so it's telling you about the probability that things will happen. If you think about it, how do you interpret that? What does it mean to say, well, 'there's a 50% chance it's going to be here'? You might say, well, no, it is there, isn't it? Well, no it isn't, there is a 50% chance it's going to be there. That's how the theory works.

Robyn Williams: Yes, I must say I find entanglement, which you deal with in that book, of something splitting and being here and there, and 'here' could be light years away from 'there', and yet in some ways they are still unified.

Brian Cox: Yes, it's very interesting actually because in the book we do what is called non-relativistic quantum mechanics, and then it is absolutely true...if you say I put a particle at a point, so technically there, I know exactly where it is. Where is it at the next instance? The answer is anywhere in the universe with equal probability. So there's no regard for relativity at all in this theory, it just seems odd because relativity tells us that influences can't travel faster than the speed of light, so there should be some restriction.

In quantum field theory, which is the relativistic version of this, there is a modification, a quite severe modification to that, but still there is an apparent violation of the spirit of Einstein's theory of relativity. Things instantaneously seem to shift. One example of this is something called the EPR paradox, which bothered Einstein a lot. So we've said this in the book. And a physicist called Sean Carroll, who is an excellent physicist over on the West Coast of America, I think he's at Stanford, and he questioned this, he said no, I don't believe that, I think you're misrepresenting the theory because I think that it surely is the case that relativity is respected.

So we thought, okay, we'll prove it. We think that the book is right. It's technically right, but within spirit is it right? And we couldn't prove it. So my friend Jeff Forshaw, who is a theoretical physicist, couldn't do the integrals, it is a technical problem. And so we thought okay, someone must have proved this, maybe we're wrong, but someone...and we looked back and Feynman had actually done some work on this in the early days, and he couldn't do it either, because you can't do the integrals, they are too hard.

Robyn Williams: Well, if Feynman can't do it!

Brian Cox: So it actually turns out to be a very interesting problem. So I don't know actually at the moment. What I'm doing is we've started a research project, which is the interesting thing, based on this popular book, and I'm writing code at the moment because I think you can do these integrals now with computers, but back in the old foundational days in the '60s and '70s, everyone is fairly sure that everything works out but no one has actually shown precisely how it works out. So it's actually quite an interesting problem. So it may be that that statement, 'everything that can happen does happen', it may be that in relativistic quantum field theory it should be watered down somewhat, but actually I don't know at the moment. But I think it's an interesting example of how you teach or you simplify something for a book and you say something which is technically correct as far as you can tell but there's a lot of nuance in there actually which we are still investigating.

Robyn Williams: You said 'popular book', there is lots of nuance, but also there are several equations, and that's probably the most technical of your books. How did it go with the public?

Brian Cox: It's done very well. The response tends to be split. If you look on Amazon, for example, you look at the comments, then there are people who love it because it does explain the theory and it does derive things, and indeed at the end we derive something called the Chandrasekhar limit, which is effectively the maximum mass of a white dwarf star, what it really is is the maximum mass of a blob of matter that can be held up by quantum effects basically. You find out it's 1.4 times the mass of the Sun, which is indeed correct, it is one of the great calculations in physics. So we calculate that.

And so if people pay attention to the book and really want to understand the theory, then the feedback is that they do and they feel wonderful and they give it five stars. But there's another set of people that want a more popular book and they really would just like a descriptive book. But I think there are a lot of descriptive books about quantum mechanics, so that's not what we set out to do, we set out to write a book which actually explains the theory as deeply as we could but with no mathematics that is harder than school maths. So if you're comfortable doing things like Pythagoras and stuff, then our view as authors is that you can follow the book if you want to. And some bits might be hard and you might have to think, but then...so it's a different book.

Robyn Williams: Yes. The most impressive thing is that it's difficult enough and yet the public responds to that sort of thing. But what I want to ask you now is something that I actually saw at the time the Higgs boson seemed to be confirmed, and this was a remarkable announcement coming from two teams, and I saw you say in public that this was the most important significant discovery of your lifetime. Why so?

Brian Cox: The first thing to say is this theory is called the standard model of particle physics, it's a quantum theory, and it's a description of three of the four forces of nature. So other than gravity, it describes at a fundamental level everything we know about the way the universe works at the basic level. So it's electricity and magnetism, the strong nuclear force, the weak nuclear force. And it contains this thing called the Higgs mechanism, it's a unique mechanism in physics. It essentially says that less than a billionth of a second after the Big Bang, something condensed out, if you like, into the vacuum, so that the technical word for this Higgs field, it's a condensate. So you can imagine almost it's similar physics to water condensing out onto a pane of glass. So a cold pane of glass and you see liquid water appear on it. So the water vapour changes state, it becomes liquid. It's very similar to that actually in some ways. So it's a radical suggestion.

And then the suggestion is that things get mass by interacting with this condensate, almost bouncing off Higgs particles, it's slightly looser language, but essentially zigzagging through this stuff, and that's how things get mass. So it's a very odd theory. And actually more than that, if you calculate naïvely the energy wrapped up in this Higgs field, in every cubic metre of space, you find out that it is greater than the solar energy output in 1,000 years. So more energy in the Sun output…it's a very odd theory. It actually turns out that that's correct, so that's odd in itself. We found that that was a true description of nature.

What I think is even more interesting is it was in there, that proposal was made for mathematical reasons by Peter Higgs and others back in the 1960s, so it was almost an observation that this is a cool...almost a trick. Maybe that's devaluing it slightly, but it's almost like a cool trick. We can give masses to things, preserve the beauty or the symmetry of these equations if we are allowed this rather strange mechanism. So I think that it is one of the great demonstrations of the power of mathematics in theoretical physics, predicting something that is real. So this is not esoteric, this is absolutely the reason why the fundamental particles get their mass, so why an electron has mass. So we now know that's correct.

We don't know yet which Higgs particle it is. Technically if you were being absolutely precise we don't actually know if we've discovered the Higgs particle, what we've discovered is it's a boson definitely, and it's a boson about 126 times the mass of the proton, give or take. So it's a boson with the right mass and some of the right properties to be a Higgs.

But actually the challenge now at CERN is to measure how this thing decays. We've seen it decaying to two photons, for example, which is how we know it's a boson, but we want to see it decaying to electrons or...all the different things it can decay into, and see if that matches the predictions of the basic Higgs theory, the so-called standard model, or is it a different one. There are theories where there are five Higgses, for example. So could it be one of a number of Higgs particles? We don't know that yet.

Robyn Williams: And will they found that out in the near future, because they are closing down CERN, the Large Hadron Collider, for a refit.

Brian Cox: Yes, we've got a huge amount of data now, and actually the LHC should have been shut down before now. Basically these maintenance shutdowns are very difficult to do on the LHC because it's cold, so it runs at -271° or so, very close to absolute zero. So it takes a month or so to warm the thing up and a month to cool it down. And obviously you can have problems when you warm things up and cool things down. So you try to not do maintenance on the machine. So you have long maintenance things. So it's a planned maintenance which has already been pushed back because it's running so well. It is running beyond anybody's expectations, which is a tremendous achievement for this thing because you must remember it is the most complicated machine, by some measure, that we'd ever built in history. And the fact that it works better than expected and has already made this discovery, which is really one of the key reasons the machine was built, I think is remarkable.

Robyn Williams: Brian Cox is Professor of Particle Physics at Manchester, and his book, written with Jeff Forshaw, is The Quantum Universe: Everything That Can Happen Does Happen. And he'll be in a series in the summer on RN called The Infinite Monkey Cage. More on that in The Science Show in December.

Cupol :

paul leonard hill :

24 Nov 2012 8:20:49pm

I reckon that the science of Quantum Mechanics lies at the religious end of the spectrum, ie the more counter intuitive and irrational it is the more likely it is to be correct. Faith not reason. For instance the Universe is supposed to be filling up with invisible 'dark energy' which is essentially space. So space is not empty but filled with dark energy, IS dark energy. Yet no less a luminary than Paul Davies says that the Universe has to expand to accommodate the HEAT generated by the formation of stars, a 'heatsink'. When air is compressed in an air compressor it's temperature increases, ie when X amounts of heat energy is put into a smaller volume it get hotter. Therefore if it put into a larger volume it's temperature must decrease. As there is no limitation the expansion of the Universe more heat generated by an increase in star formation must simply mean an expanding Universe to maintain a uniform average temperature.

Therefore the beginning of the ACCELERATION of the expansion of the Universe around 7 billion years ago must theoretically coincide with an acceleration in the formation of stars. When a large star runs out of fuel so no more thermonuclear reactions are taking place in it's core, it implodes in on itself because there is no more pressure outward to counterbalance the gravitation field pressing inward and blasts off the OUTER layers in a supernova. A neutron star is born and if it's big enough it becomes a black hole. Now despite it being composed of densely packed neutrons, with a massive gravitational field IT MUST BE COLD because there are no thermonuclear reactions taking place within it. If it is a black hole big enough to gobble a star which strays into its 'event horizon' it not that the heat and light of that star cannot get out because the massive gravitational field of the black prevent same, the heat and light of the star are EXTINGUISHED because all of its protons and electrons are crushed into each other to form NEUTONS to add to the neutrons already in the nuclei of its atoms (except hydrogen).

So no more thermonuclear reactions can take place, no more evolution of the element up unto the heaviest uranium, because the entire layered structure of the star has been destroyed along with the star itself, no more information of 'starness'. It just adds more neutrons to the black hole which expands in size accordingly to gobble up ever more stars and eventually presumably entire galaxies. As this process takes place the Universe must therefore cool down and contract. Finally with no more galaxies to keep their super massive black holes and their neutrons apart they get drawn into one giant black hole which implodes in on itself to form NOTHING. Then comes the BANG RESULTING from the crunch. No bang no crunch, no crunch no bang. Life and death. Yin and Yang. Just substitute heat for the highly speculative 'dark energy' and it all becomes simple, TOO simple for the Quantum

paul leonard hill :

28 Nov 2012 9:21:41pm

Correction.

In the above I stated that black holes are composed of densely packed neutrons. However going online most sites state that their gravitational field is so immense that even the neutrons disappear? So what the hell are they? They are not space which is both expanding and filled with things like photons, neutrinos and perhaps electrons which appear and disappear. Are they simply a hole which can only exist as long as there is something in which to have a hole, ie matter, stars, gas, dust, radiation etc. Are they ultimate cold, way below absolute zero? Reverse heat?

One thing that is patently missing in western science and probably eastern science as well, is a very solid concept of yin and yang, acidity in relationship to alkalinity, hot relative to cold, light only made visible by the dark. I first got hit with this when reading a book about 40 years ago by the (anti?) Psychiatrist Andrew Weil, when he stated in the natural mind that hippies create police and police create hippies, not a very good analogy, but getting at the point that we live in a cybernetic world and universe, of complementary opposites. You can't have one without the other. Hot by itself is just nyet.

With a supernova the material blown off can be the beginning of a galaxy whilst the neutron star which forms can be it's core which, once it becomes big enough, by say merging with another neutron star becomes a black hole, its material blown off also merging with the former. Thus galaxy and black hole, essential to each other's formation, have their inception at the same time. But black holes do seem to expand at the expense of the surrounding galaxies, meaning that eventually they will gobble up all of the matter at an accelerating rate. Whereas the universe began expanding at an accelerating rate it could contract at an accelerating rate.

Then when all matter has been consumed there is no more matter to have a hole in. Infinite energy in zero volume? What? With the bang begins polarity, positive and negative charged sub, sub, sub atomic particles. Can’t have one without the other, yin and yang. As they gain mass they swap polarity and again and again? Finally a negatively charged particle, an electron finds some sort of precise synch with a positive charged particle, a proton and we have hydrogen. What about a positron and antiproton to form anti-hydrogen. Is the the orbital relationship between electron and proton the beginning of gravity?, the massive cloud of hydrogen imploding in on itself to form the neutron. Helium, 4 hydrogens squashed to give 2 electrons, 2 protons and 2 neutrons and so on. A mega, mega nova at the beginning of the universe.

But then there'd be no hydrogen left as it's when all the hydrogen has been burned that there is no more fuel to keep the thermonuclear reactions going on in the core, so no more push outward to counteract the gravitational field pushing in.

Joe B. :

Joe B. :

04 Dec 2012 3:51:47pm

Great interview. I watched it twice! So how does a thirty minute interview take to film ;)

Brian is a very clever chap. And Robyn is so terribly modest: his questions sound like they might have come from the likes of me but I know that one day, I'll catch him out dispensing scientific jargon and vernacular to the listening audience.